Apparatus for heating air



Mar. 27, 1923.

. 1,449,598. R. GREENWOOD.

APPARATUS FOR HEATING AIR.

FILED APR-3| I922- 6 SHEETS-SHEET l- Mar. 27, 1923. 1 1,449,598.

R. GREENWOOD.

APPARATUS FOR HEATING AIR. A

FILED APR-3, 1922- 6 SHEETS-SHEET 2- a SHEETS-SHEET 4.

R GREENWOOD.

APPARATUS FOR HEATING AIR.

FILED APR 3.1922

Mar. 27, 1923.

Mar; 27, 1923.

R. GREENWOOD. APPARATUS FQR HEATING AIR.

6 SHEETSSHEET 5.

FILED AP 3. 1922.

6 SHEETS SHEET 6.

R. GREENWOOD.

APPARATUS FOR HEATING AIR.

FILED APR-3.1922.

Mar. 27 1923.

Patented Mar. 27, 1923.

1 umrro str ct;

Bowman B WPQE fes' ii Qiicziweii i -Jto can COMPANY, LIMITED, or CARLISLE, ENGLAND, anmm'rsn commits,

A'rPARA'rtfs ron HEATING AIR.

Appuca'tidn filed Apia 3",-

' ton Road, in the city of Carlisle and county of Cumberland, England, have invented a newand useful Apparatus for Heating-Air; of which the following is a specification,

This invention relates to apparatus-for heating air and hasreference to a plant for supplying heated air for such purposes plenum ventilation, domestic and hetelcook ing, heating timber drying sheds and baking biscuits. In such' -l'ant the heated air must not have been in contact with any combus tion products and must be temperature v It is the object of the presentinvention toprov'ide a heater which will" fulfill the fore going" conditions and one by which a con tinuous circulation of air may be maintained between heater and oven or the like after the first heating of fresh air suppliedto the latter. As air used in bakingor d' "i1'1gchambersis frequently exhausted there rem w'l'iilst' still in highlyheated condition it is" possible by means of the heater which is the subject of the present-invention to main tain a continuous Suppl; ofair at a'uniform temperature wi'th'out necessitating the use of excessive quantities of heatingmedium which may be of gaseous; liquidor solid form." p

According to the invention a number of conduits or flues are disposed within a cas ing each of such conduits being heated by the-combustion of fuel -therein, a number of heat distributingelements to the interior of which the products of combustion have access being arranged on the exterior of the conduits in such a manner that air is caused to take tortuous path around them for the purpose'of obtaining a uniformly heated product. lt'ispreferred that the heat distributing el'en'ie'nts should be cylindrical in form, grooved externally or provided with fins whilst where anumber of conduits so provided are employed, baflies may be utilized for the purpose of compe'lling the air under treatment to pass over 'o'r'around all of such conduitsin series. Where the invention is applied to" the heating-of an apparatus whereexhaust air its-"returned for reheating (as in' the oven described in our prior British specification at a uniforliihigh" 19a: stasim seee;

No: 126'5'9/1921-;) a hm is dep swa the conduit by which air leaves the heater-to mal-ntain'a' uniformcircuqation; I j

Reference will now he made to the-accbm-' panyirig drawings-which illustrate by way of example air heaters c'dnstructedviir-ao cordance with the: inventionand in whit'h Figure l is partly anelevation'and partly" a cross sectionof an air heater adapted fo'r' the use ofgas or oil fuel.

Figure 2 is longitudinal sectional elem: t-i'onof thesame; v 1 1 Figure 3 isa plan or the heater shown in Figures? 1 and 2, A

Figure 4 is an elevation partly in section ofua modified form of heater adapted-for the useof hardfuel. if A Figure 5 a plan partly in section of the arrangement shown in Figure 4 and Figure 6 is adiagram showing the adapta" tion of either form of heater'to lar'gescal cookery.-

The heater comprises a: number ofv conduits I of sub stantially rectangular cross section preferillustrated in Fi hts 1 to a ably having-convex upper surfacesEQ and en;

tending through a' casing 3.1'Atmospheric air or air exhausted from an ovenE-enters the casing- 3 -through i-nlets'aih'theobase 0f the casingandwhils't passing upwardsis caused; as" hereinafter described", to: passacross: the tops of the conduits T untihit leaves by an outlet 5 inithe top of the casing 31' From the'upper'surfac'e 2 of each conduit project a. number of heat-distributing mem.

bers" 6 preferablyof: cylindrical form and eaclr'p rovided with fins 7-.

The" conduits I may' be conveniently disposed as shown in two: groups, each v group comprising; a number of superimposed. pairs of closely adjacent conduits leaving-"a (zen-1 tral passage 8 betweenthe two-groups of I conduits and sidepass'ages 9 between each" i v group and one wall of thecasi'ng 3'. The passage 8 i's'bridg'ed by baffles 10 extending between alternate pairs of conduits whilst the: passages 9' are bridged by' ba'flies 1'1 alternating vertically with the baflles. 10. I

Withineach conduit are disposed rows of gas burners12 each jet 'being disposed substantially vertically beheath one 'of the; heat distributors 6. The gas inlet pipes 13 extend beyond -the front" ends ofthe conduits 1* and" areconnected to gas* trunks 14',-

fit

said inlet pipes being provided with suitable control valves 15. The front end of each conduit is adapted for the entry of air for combustion by induction or forced draught whilst the opposite end is connected to a flue 16 for the outlet of gases of combustion.

In operation air entering at the openings 4: is diverted by the lowermost baflies 10 towards each side of the casing 3 and ascends thepassages 9 until it encounters the lowermost bafiies 11 which cause the two streams of air again to flow towards the passage 8. In this manner the air is'compelled to pass across the upper surfaces of each pair of conduits 1 andis broken up. by the heat distributors 6 which owing to their'number.

and arrangement efiect a very rapid and uniform'heating of the air, every particle of which is brought into intimate and repeated contact with aflaine heated surface.

The heater above described may be adapted readily to the use of liquid fuel bysubstt tuting appropriate burners for the gas burners described and shown.

In Figures 4. and 5 are shown an air heater similar in many respects to that already described but adapted for burning coke, coal or other hard fuel. In this construction the conduits 1 are replaced by fiues 25 arranged in a setting 17 of fire brick or the like and having grate bars 18 for the reception of fuel disposed above an ashpit 19, access to grate or ashpit being by means of door 20. The upper portion of each flue 16 is formed preferably of semicircular.

cross section and provides a circulating space for the gases of combustion.

Heat distributing elements 6 similar in construction to those already described are disposed radially around the curved outer surface of each flue 16 throughout its length suflicient space being leftbetween the walls of the setting 17 and the flue to accommodate the members 6. This space is in-constant communication with air inlets 21 and a hot air outlet 22 which in the form of construction illustrated is common to both lines.

Within the arch of each iiueis disposed a series of partially circular. baflle plates 23 disposed transversely to the longitudinal axis of the flue and arranged for the purpose of ensuring an equal distribution, of gases of combustion to all parts of the surface to be heated. I

It is to be noted that the heat distributing elements (5 are arranged in rows longitudinally of the fines, the elements in each row being staggered relatively to those in adjacent rows in order 'to ensure that air entering at 21 shall take a tortuous'path in reaching the outlet 22 which it reaches in a uniformly heated condition.

It is preferred to provide each flue with a door 24: for inspection and cleaning.

Figurefi illustrates diagrammatically the application of the invention to cookery on a large scale lSllCh as is necessary in hotels, A indicating an air heater of the.form shown in Figures 1'3 or t and '5. The hot air outlet is connected by a" conduit B with a fan.@ bywhich the hot air is delivered through a second conduit D to the base of a series; of cooking ranges E from the upper ends of which the exhausted air is returned by a conduit F to the inlet ports of the heater A. In this manner a constant supply of uniformly heated air can be delivered to any form of cooking apparatus.

I claim: 7

1. Apparatus for heating air comprising a, casing, a number of heat distributing conduits disposed within said casing, a plurality of hollow heat distributing elements projecting from the top of each. conduit, and means for causing air to circulate through said casing and around said conduits. I

2. Apparatusfor heating air comprising a casing a number of heat distributing conduits disposed within said casing, a'pluconduit and bafiies within said casing to compel air to pass across the tops of said conduits in a direction at right angles to the longitudinal axis of'the conduits. H 4..Apparatus for heating air comprising a casing a number of internally heat distributing conduits disposed within said casing, a plurality of hollow cylindrical heat distributing elements projecting from the top of each conduit and communicating with their interior thereof, a plurality of fins projectinglaterally around each of said elements, and means for circulating air to be heated around said, conduits.

5. Apparatus for heating air comprising a casing, a number of heat distributing c0nduits disposed within said casing a plurality of hollow heat distributing elements project ing from said conduits, air inlets and outlets in said casing and a fan maintaining circulation of air through said casing andan. ap paratus to be heated.

6. Apparatus for heating air comprising an insulated casing a plurality of heat distributing conduits disposed in vertical rows within said casing, a plurality of hollow cylindrical heat distributing elements projecting from the upper surface of each of said conduits, baflies disposed between the inner rows of conduits and between the outer rows of conduits and the casing walls and air inlets and outlets in said casing walls.

7. Apparatus for heating air comprising a casing, a plurality of heat distributing conduits disposed therein in Vertical rows a plurality of externally ribbed hollow cylindrical heat distributing elements projecting from the upper surface of each of said con- 10 duits, baflles disposed between the inner rows of conduits and between the outer rows of conduits and the casing walls and air inlets and outlets in said casing walls.

In witness whereof I affix mysignature. ROWLAND GREENWOOD. 

